Blar i Brage NMBU på forfatter "Stefansson, Petter"
-
Estimation of phosphorus-based flame retardant in wood by hyperspectral imaging—a new method
Stefansson, Petter; Burud, Ingunn; Thiis, Thomas Kringlebotn; Gobakken, Lone; Larnøy, Erik (Journal article; Peer reviewed, 2018)It is recognised that flame retardant chemicals degrade and leach out of flame-protected wood claddings when exposed to natural weathering. However, the ability to survey the current state of a flame retardant treatment ... -
Hyperspectral imaging : algorithmic advances in variable selection and applications to wood science
Stefansson, Petter (PhD Thesis;2019:77, Doctoral thesis, 2019)According to Beer’s Law there is a linear dependence between the absorbance of a material and the concentration of an absorbing species in the material. Thus, if one is interested in modeling the concentration of an absorbing ... -
Hyperspectral NIR time series imaging used as a new method for estimating the moisture content dynamics of thermally modified Scots pine
Stefansson, Petter; Thiis, Thomas Kringlebotn; Gobakken, Lone Ross; Burud, Ingunn (Peer reviewed; Journal article, 2021)The purpose of this research is to develop a method for estimating the spatially and temporally resolved moisture content of thermally modified Scots pine (Pinus sylvestris) using remote sensing. Hyperspectral time series ... -
Monitoring and simulation of diurnal surface conditions of a wooden facade
Thiis, Thomas Kringlebotn; Burud, Ingunn; Flø, Andreas Svarstad; Kraniotis, Dimitrios; Charisi, Stergiani; Stefansson, Petter (Journal article; Peer reviewed, 2017)The hygrothermal surface conditions of a façade is important for the degradation of the façade material as well as for the energy budget of the building. The distribution of short term variations of the temperature and ... -
Much faster cross‐validation in PLSR‐modelling by avoiding redundant calculations
Liland, Kristian Hovde; Stefansson, Petter; Indahl, Ulf Geir (Peer reviewed; Journal article, 2020) -
Orders of magnitude speed increase in Partial Least Squares feature selection with new simple indexing technique for very tall data sets
Stefansson, Petter; Indahl, Ulf Geir; Liland, Kristian Hovde; Burud, Ingunn (Peer reviewed; Journal article, 2019)Feature selection is a challenging combinatorial optimization problem that tends to require a large number of candidate feature subsets to be evaluated before a satisfying solution is obtained. Because of the computational ...